This invention relates to compositions and methods useful for enhancing the wearability of contact lenses. More particularly, the invention relates to compositions and methods in which contact lenses on or in which are located non-oxidative antimicrobial components are treated to inactivate such antimicrobial components.
Various compositions, such as solutions, are used in association with contact lenses to ensure that the lenses may be safely, comfortably and conveniently worn. Contact lens care compositions often utilize at least one antimicrobial component, for example, for disinfecting contact lenses after wear.
A contact lens disinfecting composition generally has sufficient antimicrobial activity so that when the composition is contacted with a contact lens to be disinfected, microorganisms associated with the lens are killed or otherwise removed and the contact lens is effectively disinfected within a reasonable time, for example, in the range of about 0.1 hour to about 12 hours. A contact lens disinfecting composition may be termed a microbicidal composition. In contrast, a preserved contact lens care composition has sufficient antimicrobial activity, often less of such activity than is present in a contact lens disinfecting composition, so that when the composition is contacted with a contact lens substantially no increase in the microorganism population on the lens or in the composition is obtained. A preserved contact lens care composition may be termed a microbiostatic composition.
Non-oxidative antimicrobial components have been suggested for use in disinfecting contact lens. One advantage of such non-oxidative materials is that they lend themselves quite well to a one step approach to disinfecting contact lens. For example, the non-oxidative antimicrobial component can be included in a multi-purpose contact lens care solution which is used to disinfect the lens. The disinfected lens is then taken directly from the solution and placed in the eye. No rinsing or other processing is required. As the name implies, such multi-purpose solutions can be used for purposes other than disinfecting contact lenses, such as rinsing, storing and rewetting contact lenses.
Although this approach to contact lens care has proven to be quite effective and very convenient, some degree of ocular sensitivity to non-oxidative antimicrobial components has been experienced, or at least perceived, by contact lens wearers. Even when such non-oxidative materials are used as preservatives, some degree of actual or perceived ocular sensitivity may occur. Such non-oxidative antimicrobial components tend to accumulate on or in contact lenses over time (and repeated treatments with multi-purpose solutions), resulting in increased ocular sensitivity.
It would be advantageous to provide a contact lens care system in which the ocular sensitivity to non-oxidative antimicrobial components is reduced or even eliminated and contact lens wearability is enhanced.